A physiologically-based digital twin for alcohol consumption-predicting real-life drinking responses and long-term plasma PEth.

Alcohol consumption is associated with a wide variety of preventable health complications and is a major risk factor for all-cause mortality in the age group 15-47 years. To reduce dangerous drinking behavior, eHealth applications have shown promise. A particularly interesting potential lies in the combination of eHealth apps with mathematical models. However, existing mathematical models do not consider real-life situations, such as combined intake of meals and beverages, and do not connect drinking to clinical markers, such as phosphatidylethanol (PEth). Herein, we present such a model which can simulate real-life situations and connect drinking to long-term markers. The new model can accurately describe both estimation data according to a χ2 -test (187.0 < Tχ2 = 226.4) and independent validation data (70.8 < Tχ2 = 93.5). The model can also be personalized using anthropometric data from a specific individual and can thus be used as a physiologically-based digital twin. This twin is also able to connect short-term consumption of alcohol to the long-term dynamics of PEth levels in the blood, a clinical biomarker of alcohol consumption. Here we illustrate how connecting short-term consumption to long-term markers allows for a new way to determine patient alcohol consumption from measured PEth levels. An additional use case of the twin could include the combined evaluation of patient-reported AUDIT forms and measured PEth levels. Finally, we integrated the new model into an eHealth application, which could help guide individual users or clinicians to help reduce dangerous drinking.

Liver stiffness predicts progression to liver-related events in patients with chronic liver disease - A cohort study of 14 414 patients.

BACKGROUND & AIMS: Liver stiffness measurement (LSM) by vibration-controlled transient elastography (VCTE) is a non-invasive diagnostic biomarker of liver fibrosis. It is uncertain if LSM can predict risk for future liver-related outcomes in large, heterogenous populations. METHODS: This Swedish multi-centre cohort study included patients (n = 14 414) from 16 sites who underwent LSM by VCTE between 2008 and 2020. Outcomes were ascertained from national registers. We investigated progression to cirrhosis with portal hypertension or hepatocellular carcinoma (HCC), separately. Cox regression was used to obtain hazard ratios (HRs). Harrel's C-index was used to measure discrimination of VCTE. RESULTS: Included patients had a median age of 46 (interquartile range 34-57), median LSM of 5.9 kPa (4.6-8.0), 59% were male, and the majority had hepatitis C (50.1%). During a median follow-up of 5.9 (4.3-8.0) years, 402 patients (2.7%) developed cirrhosis with portal hypertension. In patients with an LSM ≥25 kPa, 28.7% developed cirrhosis with portal hypertension within 5 years of follow-up, while only .6% of patients with an LSM <10 kPa did. This translated to a HR of 48.3 (95% confidence interval = 37.6-62.0). VCTE had a high discriminative ability, with C-indices above .80 for most liver diseases, including .82 for MASLD. Similar findings were seen for incident HCC. CONCLUSIONS: Increased LSM by VCTE was associated with an increased risk of progression to both cirrhosis with portal hypertension, and to HCC, and had a high discriminative ability across different aetiologies of chronic liver diseases. These results support the use of VCTE to guide follow-up and treatment decisions.

Activin A levels in metabolic dysfunction-associated steatotic liver disease associates with fibrosis and the PNPLA3 I148M variant.

BACKGROUND: Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most prevalent chronic liver condition worldwide. There is an urgent need to develop new biomarkers to assess disease severity and to define patients with a progressive phenotype. Activin A is a new promising biomarker with conflicting results about liver fibrosis. In this study we investigate levels of Activin A in patients with biopsy proven MASLD. We assess levels of Activin A in regard to fibrosis stage and genetic variant I148M in the patatin-like phospholipase domain-containing protein 3 (PNPLA3). METHODS: Activin A levels were assessed in plasma samples from patients with biopsy-proven MASLD in a cross-sectional study. All patients were clinically evaluated and the PNPLA3 I148M genotype of the cohort was assessed. FINDINGS: 41 patients were included and 27% of these had advanced fibrosis. In MASLD patients with advanced fibrosis, Activin A levels was higher (p < 0.001) and could classify advanced fibrosis with an AUROC for activin A of 0.836 (p < 0.001). Patients homozygous for PNPLA3 I148M G/G had higher levels of activin A than non-homozygotes (p = 0.027). CONCLUSIONS: Circulating activin A levels were associated with advanced fibrosis and could be a potential blood biomarker for identifying advanced fibrosis in MASLD. Patients with the risk genotype PNPLA3 I148M G/G had higher levels of activin A proposing activin A as a contributor of the transition from simple steatosis to a fibrotic phenotype.

Altered probe pressure and body position increase diagnostic accuracy for men and women in detecting hepatic steatosis using quantitative ultrasound.

OBJECTIVES: To evaluate the diagnostic performance of ultrasound guided attenuation parameter (UGAP) for evaluating liver fat content with different probe forces and body positions, in relation to sex, and compared with proton density fat fraction (PDFF). METHODS: We prospectively enrolled a metabolic dysfunction-associated steatotic liver disease (MASLD) cohort that underwent UGAP and PDFF in the autumn of 2022. Mean UGAP values were obtained in supine and 30° left decubitus body position with normal 4 N and increased 30 N probe force. The diagnostic performance was evaluated by the area under the receiver operating characteristic curve (AUC). RESULTS: Among 60 individuals (mean age 52.9 years, SD 12.9; 30 men), we found the best diagnostic performance with increased probe force in 30° left decubitus position (AUC 0.90; 95% CI 0.82-0.98) with a cut-off of 0.58 dB/cm/MHz. For men, the best performance was in supine (AUC 0.91; 95% CI 0.81-1.00) with a cut-off of 0.60 dB/cm/MHz, and for women, 30° left decubitus position (AUC 0.93; 95% CI 0.83-1.00), with a cut-off 0.56 dB/cm/MHz, and increased 30 N probe force for both genders. No difference was in the mean UGAP value when altering body position. UGAP showed good to excellent intra-reproducibility (Intra-class correlation 0.872; 95% CI 0.794-0.921). CONCLUSION: UGAP provides excellent diagnostic performance to detect liver fat content in metabolic dysfunction-associated steatotic liver diseases, with good to excellent intra-reproducibility. Regardless of sex, the highest diagnostic accuracy is achieved with increased probe force with men in supine and women in 30° left decubitus position, yielding different cut-offs. CLINICAL RELEVANCE STATEMENT: The ultrasound method ultrasound-guided attenuation parameter shows excellent diagnostic accuracy and performs with good to excellent reproducibility. There is a possibility to alter body position and increase probe pressure, and different performances for men and women should be considered for the highest accuracy. KEY POINTS: • There is a possibility to alter body position when performing the ultrasound method ultrasound-guided attenuation parameter. • Increase probe pressure for the highest accuracy. • Different performances for men and women should be considered.

Long-term major adverse liver outcomes in 1,260 patients with non-cirrhotic NAFLD.

Background & Aims: Long-term studies of the prognosis of NAFLD are scarce. Here, we investigated the risk of major adverse liver outcomes (MALO) in a large cohort of patients with NAFLD. Methods: We conducted a cohort study with data from Swedish university hospitals. Patients (n = 1,260) with NAFLD without cirrhosis were diagnosed through biopsy or radiology, and had fibrosis estimated through vibration-controlled transient elastography, biopsy, or FIB-4 score between 1974 and 2020 and followed up through 2020. Each patient was matched on age, sex, and municipality with up to 10 reference individuals from the general population (n = 12,529). MALO were ascertained from Swedish national registers. The rate of events was estimated by Cox regression. Results: MALO occurred in 111 (8.8%, incidence rate = 5.9/1,000 person-years) patients with NAFLD and 197 (1.6%, incidence rate = 1.0/1,000 person-years) reference individuals during a median follow up of 13 years. The rate of MALO was higher in patients with NAFLD (hazard ratio = 6.6; 95% CI = 5.2-8.5). The risk of MALO was highly associated with the stage of fibrosis at diagnosis. In the biopsy subcohort (72% of total sample), there was no difference in risk between patients with and without non-alcoholic steatohepatitis. The 20-year cumulative incidences of MALO were 2% for the reference population, 3% for patients with F0, and 35% for F3. Prognostic information from biopsy was comparable to FIB-4 (C-indices around 0.73 vs. 0.72 at 10 years). Conclusions: This study provides updated information on the natural history of NAFLD, showing a high rate of progression to cirrhosis in F3 and a similar prognostic capacity of non-invasive tests to liver biopsy. Impact and implications: Several implications for clinical care and future research may be noted based on these results. First, the risk estimates for cirrhosis development are important when communicating risk to patients and deciding on clinical monitoring and treatment. Estimates can also be used in updated health-economic evaluations, and for regulatory agencies. Second, our results again highlight the low predictive information obtained from ascertaining NASHstatus by histology and call for more objective means by which to define NASH. Such methods may include artificial intelligence-supported digital pathology. We highlight that NASH is most likely the causal factor for fibrosis progression in NAFLD, but the subjective definition makes the prognostic value of a histological NASH diagnosis of limited value. Third, the finding that prognostic information from biopsy and the very simple Fibrosis-4 score were comparable is important as it may lead to fewer biopsies and further move the field towards non-invasive means by which to define fibrosis and, importantly, use non-invasive tests as outcomes in clinical trials. However, all modalities had modest discriminatory capacity and new risk stratification systems are needed in NAFLD. Repeated measures of non-invasive scores may be a potential solution.

Misclassified Alcohol-related Liver Disease is Common in Presumed Metabolic Dysfunction-associated Steatotic Liver Disease and Highly Increases Risk for Future Cirrhosis.

BACKGROUND & AIMS: Alcohol overconsumption is a risk factor for disease progression in patients with presumed metabolic dysfunction-associated steatotic liver disease (MASLD). How commonly this occurs and how it affects progression to major adverse liver outcomes (MALOs) is not well known. METHODS: We did a register-based cohort study, including all patients with a diagnosis of MASLD in Sweden between 1987 and 2020. Patients were stratified on co-occurrence of diagnoses of alcohol-related liver disease (ALD) or alcohol use disorder (AUD) prior to MASLD diagnosis. Incident MALOs were derived from national registers. Cox regression was used to calculate hazard ratios (HRs) for incident MALO. RESULTS: A total of 15,107 patients with MASLD were identified. The median age was 55 years, and 52% were female. Of the patients, 1843 (12%) had a prior diagnosis of ALD or AUD. During follow-up, a further 787 patients (5.2%) received a diagnosis of ALD or AUD. Patients with previous ALD or AUD diagnoses at or before baseline had considerably higher rates of MALOs compared with patients without (19.5% vs 7.8%; adjusted HR, 3.12; 95% confidence interval, 2.74-3.55). Acquiring an ALD or AUD diagnosis after MASLD diagnosis was associated with higher rates of MALOs (adjusted HR, 5.81; 95% confidence interval, 4.90-6.88). CONCLUSIONS: ALD or AUD is commonly diagnosed prior to or after MASLD diagnosis. Such patients have considerably higher rates of progression to MALOs. Correctly separating between MASLD and ALD is vital to assess prognosis.

A rapid, non-invasive, clinical surveillance for CachExia, sarcopenia, portal hypertension, and hepatocellular carcinoma in end-stage liver disease: the ACCESS-ESLD study protocol.

BACKGROUND: Liver cirrhosis, the advanced stage of many chronic liver diseases, is associated with escalated risks of liver-related complications like decompensation and hepatocellular carcinoma (HCC). Morbidity and mortality in cirrhosis patients are linked to portal hypertension, sarcopenia, and hepatocellular carcinoma. Although conventional cirrhosis management centered on treating complications, contemporary approaches prioritize preemptive measures. This study aims to formulate novel blood- and imaging-centric methodologies for monitoring liver cirrhosis patients. METHODS: In this prospective study, 150 liver cirrhosis patients will be enrolled from three Swedish liver clinics. Their conditions will be assessed through extensive blood-based markers and magnetic resonance imaging (MRI). The MRI protocol encompasses body composition profile with Muscle Assement Score, portal flow assessment, magnet resonance elastography, and a abbreviated MRI for HCC screening. Evaluation of lifestyle, muscular strength, physical performance, body composition, and quality of life will be conducted. Additionally, DNA, serum, and plasma biobanking will facilitate future investigations. DISCUSSION: The anticipated outcomes involve the identification and validation of non-invasive blood- and imaging-oriented biomarkers, enhancing the care paradigm for liver cirrhosis patients. Notably, the temporal evolution of these biomarkers will be crucial for understanding dynamic changes. TRIAL REGISTRATION: Clinicaltrials.gov, registration identifier NCT05502198. Registered on 16 August 2022. Link: https://classic. CLINICALTRIALS: gov/ct2/show/NCT05502198 .

A Markov model of fibrosis development in nonalcoholic fatty liver disease predicts fibrosis progression in clinical cohorts.

Disease progression in nonalcoholic steatohepatitis (NASH) is highly heterogenous and remains poorly understood. Fibrosis stage is currently the best predictor for development of end-stage liver disease and mortality. Better understanding and quantifying the impact of factors affecting NASH and fibrosis is essential to inform a clinical study design. We developed a population Markov model to describe the transition probability between fibrosis stages and mortality using a unique clinical nonalcoholic fatty liver disease cohort with serial biopsies over 3 decades. We evaluated covariate effects on all model parameters and performed clinical trial simulations to predict the fibrosis progression rate for external clinical cohorts. All parameters were estimated with good precision. Age and diagnosis of type 2 diabetes (T2D) were found to be significant predictors in the model. Increase in hepatic steatosis between visits was the most important predictor for progression of fibrosis. Fibrosis progression rate (FPR) was twofold higher for fibrosis stages 0 and 1 (F0-1) compared to fibrosis stage 2 and 3 (F2-3). A twofold increase in FPR was observed for T2D. A two-point steatosis worsening increased the FPR 11-fold. Predicted fibrosis progression was in good agreement with data from external clinical cohorts. Our fibrosis progression model shows that patient selection, particularly initial fibrosis stage distribution, can significantly impact fibrosis progression and as such the window for assessing drug efficacy in clinical trials. Our work highlights the increase in hepatic steatosis as the most important factor in increasing FPR, emphasizing the importance of well-defined lifestyle advise for reducing variability in NASH progression during clinical trials.

Incidence, prevalence and mortality of chronic liver diseases in Sweden between 2005 and 2019.

BACKGROUND: Updated data on the incidence, prevalence, and regional differences of chronic liver disease are missing from many countries. In this study, we aimed to describe time trends, incidence, prevalence, and mortality of a wide range of chronic liver diseases in Sweden. METHODS: In this register-based, nationwide observational study, patients with a register-based diagnosis of chronic liver disease, during 2005-2019, were retrieved from the Swedish National Board of Health and Welfare. Annual age-standardized incidence and mortality rates, and prevalence per 100,000 inhabitants was calculated and stratified on age, sex, and geographical region. RESULTS: The incidence of alcohol-related cirrhosis increased by 47% (2.6% annually), reaching an incidence rate of 13.1/100,000 inhabitants. The incidence rate of non-alcoholic fatty liver disease and unspecified liver cirrhosis increased by 217% and 87% (8.0 and 4.3% annually), respectively, reaching an incidence rate of 15.2 and 18.7/100,000 inhabitants, and a prevalence of 24.7 and 44.8/100,000 inhabitants. Furthermore, incidence rates of chronic hepatitis C declined steeply, but liver malignancies have become more common. The most common causes of liver-related mortality were alcohol-related liver disease and unspecified liver disease. CONCLUSION: The incidence rates of diagnosed non-alcoholic fatty liver disease, alcohol-related cirrhosis, unspecified liver cirrhosis, and liver malignancies have increased during the last 15 years. Worryingly, mortality in several liver diseases increased, likely reflecting increasing incidences of cirrhosis in spite of a decreasing rate of hepatitis C. Significant disparities exist across sex and geographical regions, which need to be considered when allocating healthcare resources.

Performance of non-invasive tests and histology for the prediction of clinical outcomes in patients with non-alcoholic fatty liver disease: an individual participant data meta-analysis.

BACKGROUND: Histologically assessed liver fibrosis stage has prognostic significance in patients with non-alcoholic fatty liver disease (NAFLD) and is accepted as a surrogate endpoint in clinical trials for non-cirrhotic NAFLD. Our aim was to compare the prognostic performance of non-invasive tests with liver histology in patients with NAFLD. METHODS: This was an individual participant data meta-analysis of the prognostic performance of histologically assessed fibrosis stage (F0-4), liver stiffness measured by vibration-controlled transient elastography (LSM-VCTE), fibrosis-4 index (FIB-4), and NAFLD fibrosis score (NFS) in patients with NAFLD. The literature was searched for a previously published systematic review on the diagnostic accuracy of imaging and simple non-invasive tests and updated to Jan 12, 2022 for this study. Studies were identified through PubMed/MEDLINE, EMBASE, and CENTRAL, and authors were contacted for individual participant data, including outcome data, with a minimum of 12 months of follow-up. The primary outcome was a composite endpoint of all-cause mortality, hepatocellular carcinoma, liver transplantation, or cirrhosis complications (ie, ascites, variceal bleeding, hepatic encephalopathy, or progression to a MELD score ≥15). We calculated aggregated survival curves for trichotomised groups and compared them using stratified log-rank tests (histology: F0-2 vs F3 vs F4; LSM: <10 vs 10 to <20 vs ≥20 kPa; FIB-4: <1·3 vs 1·3 to ≤2·67 vs >2·67; NFS: <-1·455 vs -1·455 to ≤0·676 vs >0·676), calculated areas under the time-dependent receiver operating characteristic curves (tAUC), and performed Cox proportional-hazards regression to adjust for confounding. This study was registered with PROSPERO, CRD42022312226. FINDINGS: Of 65 eligible studies, we included data on 2518 patients with biopsy-proven NAFLD from 25 studies (1126 [44·7%] were female, median age was 54 years [IQR 44-63), and 1161 [46·1%] had type 2 diabetes). After a median follow-up of 57 months [IQR 33-91], the composite endpoint was observed in 145 (5·8%) patients. Stratified log-rank tests showed significant differences between the trichotomised patient groups (p<0·0001 for all comparisons). The tAUC at 5 years were 0·72 (95% CI 0·62-0·81) for histology, 0·76 (0·70-0·83) for LSM-VCTE, 0·74 (0·64-0·82) for FIB-4, and 0·70 (0·63-0·80) for NFS. All index tests were significant predictors of the primary outcome after adjustment for confounders in the Cox regression. INTERPRETATION: Simple non-invasive tests performed as well as histologically assessed fibrosis in predicting clinical outcomes in patients with NAFLD and could be considered as alternatives to liver biopsy in some cases. FUNDING: Innovative Medicines Initiative 2.

Adverse muscle composition is a significant risk factor for all-cause mortality in NAFLD.

Background & Aims: Adverse muscle composition (MC) (i.e., low muscle volume and high muscle fat) has previously been linked to poor functional performance and comorbidities in non-alcoholic fatty liver disease (NAFLD). In this study we aimed to investigate associations of all-cause mortality with liver fat, NAFLD, and MC in the UK Biobank imaging study. Methods: Magnetic resonance images of 40,174 participants were analyzed for liver proton density fat fraction (PDFF), thigh fat-free muscle volume (FFMV) z-score, and muscle fat infiltration (MFI) using the AMRA® Researcher. Participants with NAFLD were sex-, age-, and BMI-matched to participants without NAFLD with low alcohol consumption. Adverse MC was identified using previously published cut-offs. All-cause mortality was investigated using Cox regression. Models within NAFLD were crude and subsequently adjusted for sex, age, BMI (M1), hand grip strength, physical activity, smoking, alcohol (M2), and previous cancer, coronary heart disease, type 2 diabetes (M3). Results: A total of 5,069 participants had NAFLD. During a mean (±SD) follow-up of 3.9 (±1.4) years, 150 out of the 10,138 participants (53% men, age 64.4 [±7.6] years, BMI 29.7 [±4.4] kg/m2) died. In the matched dataset, neither NAFLD nor liver PDFF were associated with all-cause mortality, while all MC variables achieved significance. Within NAFLD, adverse MC, MFI and FFMV z-score were significantly associated with all-cause mortality and remained so in M1 and M2 (crude hazard ratios [HRs] 2.84, 95% CI 1.70-4.75, p <0.001; 1.15, 95% CI 1.07-1.24, p <0.001; 0.70, 95% CI 0.55-0.88, p <0.001). In M3, the relationship was attenuated for adverse MC and FFMV z-score (adjusted HRs 1.72, 95% CI 1.00-2.98, p = 0.051; 0.77, 95% CI 0.58-1.02, p = 0.069) but remained significant for MFI (adjusted HR 1.13, 95% CI 1.01-1.26, p = 0.026). Conclusions: Neither NAFLD nor liver PDFF was predictive of all-cause mortality. Adverse MC was a strong predictor of all-cause mortality in individuals with NAFLD. Impact and implications: Individuals with fatty liver disease and poor muscle health more often suffer from poor functional performance and comorbidities. This study shows that they are also at a higher risk of dying. The study results indicate that measuring muscle health (the patient's muscle volume and how much fat they have in their muscles) could help in the early detection of high-risk patients and enable targeted preventative care.

Moderate alcohol consumption is associated with significant fibrosis progression in NAFLD.

The effect of moderate alcohol consumption on NAFLD histology is disputed. Assessment of alcohol consumption is commonly performed with interview or questionnaires. Phosphatidylethanol (PEth) in blood is a highly sensitive and specific alcohol biomarker, which only forms in the presence of ethanol. PEth has hitherto not been evaluated in longitudinal NAFLD studies. This study aimed to examine the impact of moderate alcohol consumption on histologic progression and evaluate the utility of PEth in NAFLD. NAFLD patients with serial biopsies were reviewed for inclusion in the study. At baseline, all patients reported alcohol consumption <140 g/week. Anthropometric and biochemical measurements were performed at baseline and follow-up. Alcohol consumption was assessed thoroughly at follow-up with clinical interview, the Alcohol Use Disorder Identification Test-Consumption (AUDIT-C) questionnaire, and analysis of PEth in whole blood. Eighty-two patients were included. Mean follow-up time was 17.2 years (SD±6.0). Patients with significant fibrosis progression (defined as progression of ≥2 stages or development of cirrhosis-related complications) reported higher alcohol consumption and had significantly higher PEth. Consumption >66-96 g/week (but <140 g) (i.e. moderate alcohol consumption) was associated with increased risk of significant fibrosis progression compared with no or low consumption. PEth ≥48 ng/mL and binge drinking showed the highest risk for significant fibrosis progression (aOR: 5.9; 95% CI: 1.6-21.4) and aOR: 5.1; 95% CI: 1.4-18.1, respectively). NAFLD patients consuming moderate amounts of alcohol are at increased risk for significant fibrosis progression and development of cirrhosis-related complications. PEth is a potential biomarker to assess harmful alcohol consumption in NAFLD. Patients reporting moderate consumption or exhibiting PEth ≥48 ng/mL should be advised to reduce alcohol consumption.

Effect of common genetic variants on the risk of cirrhosis in non-alcoholic fatty liver disease during 20 years of follow-up.

BACKGROUND AND AIMS: Several genotypes associate with a worse histopathological profile in patients with non-alcoholic fatty liver disease (NAFLD). Whether genotypes impact long-term outcomes is unclear. We investigated the importance of PNPLA3, TM6SF2, MBOAT7 and GCKR genotype for the development of severe outcomes in NAFLD. METHOD: DNA samples were collected from 546 patients with NAFLD. Advanced fibrosis was diagnosed by liver biopsy or elastography. Non-alcoholic steatohepatitis (NASH) was histologically defined. Additionally, 5396 controls matched for age, sex and municipality were identified from population-based registers. Events of severe liver disease and all-cause mortality were collected from national registries. Hazard ratios (HRs) adjusted for age, sex, body mass index and type 2 diabetes were estimated with Cox regression. RESULTS: In NAFLD, the G/G genotype of PNPLA3 was associated with a higher prevalence of NASH at baseline (odds ratio [OR] 3.67, 95% CI = 1.66-8.08), but not with advanced fibrosis (OR 1.81, 95% CI = 0.79-4.14). After up to 40 years of follow-up, the PNPLA3 G/G genotype was associated with a higher rate of severe liver disease (adjusted hazard ratio [aHR] 2.27, 95% CI = 1.15-4.47) compared with the C/C variant. NAFLD patients developed cirrhosis at a higher rate than controls (aHR 9.00, 95% CI = 6.85-11.83). The PNPLA3 G/G genotype accentuated this rate (aHR 23.32, 95% = CI 9.14-59.47). Overall mortality was not affected by any genetic variant. CONCLUSION: The PNPLA3 G/G genotype is associated with an increased rate of cirrhosis in NAFLD. Our results suggest that assessment of the PNPLA3 genotype is of clinical relevance in patients with NAFLD to individualize monitoring and therapeutic strategies.

Hepatic patatin-like phospholipase domain-containing 3 levels are increased in I148M risk allele carriers and correlate with NAFLD in humans.

In nonalcoholic fatty liver disease (NAFLD) the patatin-like phospholipase domain-containing 3 (PNPLA3) rs738409 variant is a contributor. In mice, the Pnpla3 148M variant accumulates on lipid droplets and probably leads to sequestration of a lipase cofactor leading to impaired mobilization of triglycerides. To advance our understanding of the localization and abundance of PNPLA3 protein in humans, we used liver biopsies from patients with NAFLD to investigate the link to NAFLD and the PNPLA3 148M genotype. We experimentally qualified an antibody against human PNPLA3. Hepatic PNPLA3 protein fractional area and localization were determined by immunohistochemistry in biopsies from a well-characterized NAFLD cohort of 67 patients. Potential differences in hepatic PNPLA3 protein levels among patients related to degree of steatosis, lobular inflammation, ballooning, and fibrosis, and PNPLA3 I148M gene variants were assessed. Immunohistochemistry staining in biopsies from patients with NAFLD showed that hepatic PNPLA3 protein was predominantly localized to the membranes of small and large lipid droplets in hepatocytes. PNPLA3 protein levels correlated strongly with steatosis grade (p = 0.000027) and were also significantly higher in patients with lobular inflammation (p = 0.009), ballooning (p = 0.022), and significant fibrosis (stage 2-4, p = 0.014). In addition, PNPLA3 levels were higher in PNPLA3 rs738409 148M (CG, GG) risk allele carriers compared to 148I (CC) nonrisk allele carriers (p = 0.0029). Conclusion: PNPLA3 protein levels were associated with increased hepatic lipid content and disease severity in patients with NAFLD and were higher in PNPLA3 rs738409 (148M) risk allele carriers. Our hypothesis that increased hepatic levels of PNPLA3 may be part of the pathophysiological mechanism of NAFLD is supported.

Non-invasive diagnosis and staging of non-alcoholic fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) is considered to be the hepatic manifestation of the metabolic syndrome and is characterized by ectopic accumulation of triglycerides in the cytoplasm of hepatocytes, i.e., steatosis. NAFLD has become the most common chronic liver disease, with an estimated global prevalence of 25%. Although the majority of NAFLD patients will never experience liver-related complications, the progressive potential of NAFLD is indisputable, with 5-10% of subjects progressing to cirrhosis, end-stage liver disease, or hepatocellular carcinoma. NAFLD patients with advanced fibrosis are at the highest risk of developing cardiovascular and cirrhosis-related complications. Liver biopsy has hitherto been considered the reference method for evaluation of hepatic steatosis and fibrosis stage. Given the limitations of biopsy for widescale screening, non-invasive tests (NITs) for assessment of steatosis and fibrosis stage, including serum-based algorithms and ultrasound- and magnetic resonance-based methods, will play an increasing role in the management of NAFLD patients. This comprehensive review presents the advantages and limitations of NITs for identification of steatosis and advanced fibrosis in NAFLD. The clinical implications of using NITs to identify and manage NAFLD patients are also discussed.

Risk of cardiovascular disease and loss in life expectancy in NAFLD.

BACKGROUND AND AIMS: Conflicting evidence exists on cardiovascular disease (CVD) risk in patients with NAFLD, and data are lacking on whether NAFLD increases mortality after a CVD event. Moreover, life expectancy in NAFLD has not been studied. We therefore examined CVD risk and life expectancy in patients with NAFLD compared with the general population. APPROACH AND RESULTS: In this nationwide population-based cohort, all patients with NAFLD diagnosis and without baseline CVD (ascertaining from the Swedish National Patient Register from 1987 to 2016, n = 10,023) were matched 10:1 on age, sex, and municipality to individuals from the general population (controls, n = 96,313). CVD diagnosis and mortality were derived from national registers. Multistate models and flexible parametric survival models were used to estimate adjusted hazard ratios (aHRs) for CVD risk and loss in life expectancy due to NAFLD. We identified 1037 (10.3%) CVD events in patients with NAFLD and 4041 (4.2%) in controls. CVD risk was 2.6-fold higher in NAFLD compared with controls (aHR = 2.61, 95% CI = 2.36-2.88) and was strongest for nonfatal CVD (aHR = 3.71, 95% CI = 3.29-4.17). After a nonfatal CVD event, the risk for all-cause mortality was similar between patients with NAFLD and controls (aHR = 0.89, 95% CI = 0.64-1.25). Life expectancy in patients with NAFLD was, on average, 2.8 years lower than controls, with the highest loss of life-years when NAFLD was diagnosed in middle age (40-60 years). CONCLUSIONS: NAFLD was associated with a higher risk of nonfatal CVD but did not affect post-CVD mortality risk. Patients diagnosed with NAFLD have a lower life expectancy than the general population.

Repeated measurements of non-invasive fibrosis tests to monitor the progression of non-alcoholic fatty liver disease: A long-term follow-up study.

BACKGROUND AND AIMS: The presence of advanced hepatic fibrosis is the prime marker for the prediction of liver-related complications in non-alcoholic fatty liver disease (NAFLD). Blood-based non-invasive tests (NITs) have been developed to evaluate fibrosis and identify patients at risk. Current guidelines propose monitoring the progression of NAFLD using repeated NITs at 2-3-year intervals. The aim of this study was to evaluate the association of changes in NITs measured at two time points with the progression of NAFLD. METHODS: We retrospectively included NAFLD patients with NIT measurements in whom the baseline hepatic fibrosis stage had been assessed by biopsy or transient elastography (TE). Subjects underwent follow-up visits at least 1 year from baseline to evaluate the progression of NAFLD. NAFLD progression was defined as the development of end-stage liver disease or fibrosis progression according to repeat biopsy or TE. The following NITs were calculated at baseline and follow-up: Fibrosis-4 (FIB-4), NAFLD fibrosis score (NFS), aspartate aminotransferase to platelet ratio index (APRI) and dynamic aspartate-to-alanine aminotransferase ratio (dAAR). RESULTS: One hundred and thirty-five patients were included with a mean follow-up of 12.6 ± 8.5 years. During follow-up, 41 patients (30%) were diagnosed with progressive NAFLD. Change in NIT scores during follow-up was significantly associated with disease progression for all NITs tested except for NFS. However, the diagnostic precision was suboptimal with area under the receiver operating characteristics 0.56-0.64 and positive predictive values of 0.28-0.36 at sensitivity fixed at 90%. CONCLUSIONS: Change of FIB-4, NFS, APRI, and dAAR scores is only weakly associated with disease progression in NAFLD. Our findings do not support repeated measurements of these NITs for monitoring the course of NAFLD.

Non-invasive tests accurately stratify patients with NAFLD based on their risk of liver-related events.

BACKGROUND & AIMS: Previous studies on the prognostic significance of non-invasive liver fibrosis tests in non-alcoholic fatty liver disease (NAFLD) lack direct comparison to liver biopsy. We aimed to evaluate the prognostic accuracy of fibrosis-4 (FIB4) and vibration-controlled transient elastography (VCTE), compared to liver biopsy, for the prediction of liver-related events (LREs) in NAFLD. METHODS: A total of 1,057 patients with NAFLD and baseline FIB4 and VCTE were included in a multicenter cohort. Of these patients, 594 also had a baseline liver biopsy. The main study outcome during follow-up was occurrence of LREs, a composite endpoint combining cirrhosis complications and/or hepatocellular carcinoma. Discriminative ability was evaluated using Harrell's C-index. RESULTS: FIB4 and VCTE showed good accuracy for the prediction of LREs, with Harrell's C-indexes >0.80 (0.817 [0.768-0.866] vs. 0.878 [0.835-0.921], respectively, p = 0.059). In the biopsy subgroup, Harrell's C-indexes of histological fibrosis staging and VCTE were not significantly different (0.932 [0.910-0.955] vs. 0.881 [0.832-0.931], respectively, p = 0.164), while both significantly outperformed FIB4 for the prediction of LREs. FIB4 and VCTE were independent predictors of LREs in the whole study cohort. The stepwise FIB4-VCTE algorithm accurately stratified the risk of LREs: compared to patients with "FIB4 <1.30", those with "FIB4 ≥1.30 then VCTE <8.0 kPa" had similar risk of LREs (adjusted hazard ratio [aHR] 1.3; 95% CI 0.3-6.8), whereas the risk of LREs significantly increased in patients with "FIB4 ≥1.30 then VCTE 8.0-12.0 kPa" (aHR 3.8; 95% CI 1.3-10.9), and even more for those with "FIB4 ≥1.30 then VCTE >12.0 kPa" (aHR 12.4; 95% CI 5.1-30.2). CONCLUSION: VCTE and FIB4 accurately stratify patients with NAFLD based on their risk of LREs. These non-invasive tests are alternatives to liver biopsy for the identification of patients in need of specialized management. LAY SUMMARY: The amount of fibrosis in the liver is closely associated with the risk of liver-related complications in non-alcoholic fatty liver disease (NAFLD). Liver biopsy currently remains the reference standard for the evaluation of fibrosis, but its application is limited by its invasiveness. Therefore, we evaluated the ability of non-invasive liver fibrosis tests to predict liver-related complications in NAFLD. Our results show that the blood test FIB4 and transient elastography stratify the risk of liver-related complications in NAFLD, and that transient elastography has similar prognostic accuracy as liver biopsy. These results support the use of non-invasive liver fibrosis tests instead of liver biopsy for the management of patients with NAFLD.